1. Field of the Invention
The present invention relates to an antenna device mounted on a vehicle body such as an automobile, and more particularly, to an antenna device capable of simplifying a mounting work and reliably making connection even in the case of a composite antenna capable of receiving a plurality of frequency bandwidths.
2. Description of the Related Art
Conventionally, it has been well known that a variety of antenna devices are mounted on a vehicle body of an automobile (for example, Jpn. Pat. Appln. KOKAI Publication Nos. 2001-36315 and 2004-48599). FIGS. 14 and 15 are views each showing an example of such an antenna device. That is, an antenna device 1 is composed of: an antenna main body 2 provided at an upper side of a roof panel R; and a mount nut 10 provided at a lower side of the roof panel R. The antenna main body 2 comprises: an antenna cover 3; an antenna element 4 mounted on the antenna cover 3; a pad section 5 disposed between the antenna cover 3 and the roof panel R; and a base section (not shown) and a substrate 6 provided at the pad section 5. A matching circuit or an amplifier circuit and a duplexer are incorporated in the substrate 6.
A protrusion section 7 is provided on a lower face of the base section as shown in FIG. 15, and is inserted into an antenna mount hole. A through hole is formed at the inside of the protrusion section 7, and an AM/FM coaxial cable 8 for transmitting a signal and a power supply line 9 for supplying power to the substrate 6 are drawn via the through hole.
The mount nut 10 comprises a ground washer 11 and a nut section 12, and the ground washer 11 is assembled to be rotatable with respect to the nut section 12.
In such an antenna device 1, the antenna main body 2 is first mounted on the antenna mount hole of the roof panel R from overhead shown in FIG. 15. At this time, the antenna main body 2 is temporarily locked so as to be immobilized by a temporarily locking claw 7b or the like. Next, the coaxial cable 8 and the power supply line 9 are routed into a through hole of the protrusion section 7 of the pad section 5. Then, the nut section 12 of the mount nut 10 is helically fitted to the screw section 7a formed on an outer periphery face of the protrusion section 7. Further, when the nut section 12 is rotated, a triangle shaped distal end of the ground washer 11 is cut into a lower face side of the roof panel R shown in FIG. 15, and the antenna main body 2 is securely fixed to the roof panel R and is grounded.
The above-described antenna device has suffered from the following problem. That is, in recent year, an antenna device has often been configured as a composite antenna having incorporated therein a high frequency patch antenna such as GPS, mobile broadcast, ETC, or SDARS in addition to an AM/FM broadcast receiving antenna. Further, there may be a need for a power supply cable for use in an amplifier incorporated in the antenna main body. Therefore, the number of cables or the like must be routed into the antenna mount holes, resulting in complicated work.
In addition, there has been a need for a work of connecting their respective cables to vehicle side cables inside of the vehicle body, and there has been an increased worker's burden. Further, in the case of a connector for use in connecting a high frequency bandwidth cable, a range of an error allowable at the time of connection is very narrow, and thus, there has been a problem that skillfulness is required for a connection work.
Further, there has been a problem that work efficiency becomes low since the antenna main body is temporarily stopped in an unstable manner when the main body is positioned on the roof panel. Furthermore, since a worker must do a work with one's face being upwardly oriented, there has been a possibility that the ground washer or nut may be accidentally dropped.